Q. What is the particular solution to the differential equation dxdy=x1+y with the initial condition y(e)=1 ?
Recognize separable form: Step 1: Recognize the differential equation as a separable form. We can write it as 1+ydy=xdx.
Integrate both sides: Step 2: Integrate both sides. The left side becomes ∫1+ydy and the right side becomes ∫xdx.
Perform integration: Step 3: Perform the integration. The integral of 1+y1dy is ln∣1+y∣ and the integral of x1dx is ln∣x∣. So, ln∣1+y∣=ln∣x∣+C, where C is the integration constant.
Solve for y: Step 4: Solve for y. Exponentiate both sides to remove the logarithm, getting ∣1+y∣=eln∣x∣+C=∣x∣eC.
Apply initial condition: Step 5: Apply the initial condition y(e)=1. Substituting x=e and y=1 into ∣1+y∣=∣x∣eC gives ∣1+1∣=∣e∣eC, so 2=eC.
Solve for C: Step 6: Solve for C. Taking the natural logarithm of both sides, ln(2)=C.
Substitute back into equation: Step 7: Substitute C back into the equation for y. We have ∣1+y∣=∣x∣eln(2), or ∣1+y∣=2∣x∣.
Final solution: Step 8: Solve for y. We get 1+y=2x or y=2x−1.
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